Metal bar



Patented .lune 10, 1924.

XI'ILIAIVI` BANUM COWLES, O1? CLEVELAID HEIGI'ITS, OHIO, ASS'IG'N013, .T0 y'DI-IE WELDLESS CHAIN CORPORATION, CLEVELAND, 01-110, A. CORPORATION OF D'ELA- WARE.

METAL BAR.

Application filed December 7, 1921.

T0 aZZ w/wm t may concc'm:

Be it known that I', WILLIAM BARNUM CowLns, a citizen of the United States, residing at Cleveland Heig'hts, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Metal Bars, of which the following is a full, clear, and eXact description, reference being had to the accompanying drawm s. i

gfhis invention relates 'to a metal bar having a special cross section and which, while capable of other uses, has particular reference to a bar which shall greatly facilitate the manufacture of' weldless chain.

In my. copending application Serial No. 245,057 filed July 15, 1918, I disclosed a die roll machine for rolling weldless chain from a single homogeneous bar of cruciform cross section. In roll forging a weldless chain directly from a bar of this character I'find certain disadvantages are incurred, namely, a bar of this shape cannot bei heated uniformly and efliciently; the die rolls are subjected to unduework and strains; and lastly there is considerable waste incurred due to the large eXtrusions from the die rolls.

VVith a bar of cruciform cross section, it will be obvious that the central portion thereof contains more metal than each of the longitudinal ribs or fins which project radially therefrom. This being the case, if the bar is heated' so that the longitudinal ribs or fins are brought to the desired temperature, then the central portion containing the greater mass of metal will not have reached an equal temperature andhence unduel work is imposed on the die rollsin Shaping 'this underheated central portion. If, on the other hand, the baris hea-ted until the central portion thereof is brought to the desired temperature, then -the radially disposed fins or ribs have necessarily reached a higher temperature and are apt to be burned. In this instance also, a larger amount of fuel-and a? longer time is required for theheating.

Probably more important, however, is the fact, that with a ,bar lof cruciform cross section, the die rolls must penetrate the large central portion to a greater depth and force the displaced metal into the matrices and extrude the excess. In other words, the

central portion of a bar of this character furnishes the material to fill the matrices Serial No. 520,544.

an'd formthe extrusion and hence all of this work is imposed on the die rolls which causes rapid wear thereon. i

It;will also be apparent that the central portion of a bar of cruciform cross section provides more material than necessary to fill the die roll' matrices and hence considerable material is extruded as waste.`

Some of the objects ofthe present inventron are to provide a bar, the cross section of which shall 'be of such shape as to require a minimum of work by the die rolls in 'forging a weldless chain and thereby prolong the life of the die r0lls;`to provide a bar of this character which shall have a substanti'ally uniform cross section and `hence permit rapid and uniform heating thereof;` to i provide a bar, whose volume per unit of length shall closelyapproach the volume of the chain bar `formed therefrom and hence not only require minimum workrby the die rollslbut also reduce' the waste 'from eXtrusion to aminimum; to provide a bar of the aforesaid character which' may be easily roll forged from any stock'whose cross section is either circular or p'olygonal; to provide a bar which is 'especially `adapted for the production of weldless chains and which may be formed by die rolls of a substantial nature capableof withstan'ding the work imposed thereupon; while further objects and advantages will appear as the description proceeds.

In the'accompanying drawingwherein I have shown an 'illustrative form of myi inventi'on, Fig. l is a cross section of a' bar shaped in accordance with Vmy invention; Fig. 2 is a silnilar'view'enlarged, and also illustrating in'dotted lines the cross vsection of the bar after it has passed through the 'chain vforming' dierolls; Figs. 3 and 4 are respectively a fragmentary sectional view and aside elevation of a die roll forlrolling a bar such as shown in Figs.`l and; F ig. 5 is a cross sectionof a cruciform'bar ordinarily used in the'manufacture of weldless chain; F ig. 6 is a similar view enlarged and also showing inl dotted lines the cross section of the bar after it has passed through the chain forming rolls; and Figs. 7 an`d8 'are respectively a fragmentary cross'section and a side el'evation-o'f a'-'die roll 'for forming the cruci'form`bar shown in F igs. 5` and 6; In carrying 4out my invention, I provide four die rolls A each having a cross section similar to that shown in Fig. 3. Each die roll is formed with a centrally disposed circumferential rib 10, a grooved portion 11 disposed on each side of said rib, and beveled surfaces 12, 12 on the enter peripheral edges of said die rolls. These die rolls are positioned in a machine identical with that disclosed in my aforementioned copending application and when assembled therein, these die rolls deiine an opening whose cross section is similar to that shown in Figs. 1 and 2. A bar of metal having either a circular or polygonal cross section is then heated to the desired degree and passed through the' machine and die rolls in the usual manner. The bar which is eX- truded will have a cross section similar to that shown in Figs. l and 2 and for convenience I term this a four-bulb-bar. This bar is formed with four ribs or fins 14, each of which has a rounded outer contour and each rib or fin forms a reentrant angle with an adjacent rib, the apex of. this angle being rounded as indicated at 15. A cross section of the four-bulb-bar shows that each rib or fin 14 and the central portion 16 thereof have a substantially equal mass, and hence a bar of this type can be qnickly and uniformly heated before it is passed through suitable chain forming die rolls.

More important, however, is the fact that a bar of this cross section greatly reduces the work of the inatrices on the chain forming die rolls, as it approaches more closely in shape the cross section of the chain bar produced by said matrices of the chain forming die rolls. By referring to Fig. 2 it will be observed that when a bar of' this type is passed through the chain forniing die rolls, the matrices on these die rolls must penetrate the central portion 1G at certain spaced points to a depth which closely approaches the longitudinal center of the bar. The actnal depth penetratcd in the central portion of a four-bulb-bar by the die roll matrices is indicated by the distance X and the metal displaced serves to till the niatrices of the chain die roll and the excess is extrnded as thin webs between the die rolls.

In Fig. 6 I have shown. a cross section of the nsual crnciforin bar and indicated in dotted lines is the shape of the chain bar. In this instance the actnal distance penetrated in the central portion 20 is indicated by the dist-ance Y. For purposes of comparison between the distances X and Y the enlarged cross Sections ofy the fonr-bnlb-bar and cruciform bar have been drawn to the same scale and it willbe at once apparent that the distance X is approxiniately 33% less than the distance Y. It .will be obvious that the die ymatrices rolling a four-bulb chain-bar willl not be subjected to nearly S0 much-work and strain as in the case of a cruciform bar.` Also in the case of a fourbnlb bar, the penetrating portions of the die matrices will not be snrrounded by so great a mass of heated metal as in the case of the cruciform bar. It might be fnrther noted that a cleaner and more sharply defined chain bar can be produced when the die matrices do not penetrate so great a mass of metal.

In the case of the cruciform bar a larger mass of metal is displaced from the central portion than in the case of the four-billbbar and hence the displaced metal in the cruciform bar will more than fill the die matrices and produce more waste in the form of extrusions than with the four-bull)- bar.

From the foregoing description and drawing it will be apparent that a. four-bulb-bar possesses decided advantages over a crnciform bar and greatly facilitates the manufacture of Weldless chain, as a major portion of the work of the chain forming die roll is performed by the prelin'iinary die rolls which shape the (round or polygonal bar) material into a four-bulb-bar.

IAIaving thus described my invention, what I claim is:

1. A bar of metal having a central portion and radially disposed ribs projecting therefrom, each of said ribs and the central portion of said bar having substantially eqnal masses of metal.

2. A bar of metal having a central. portion and radially disposed ribs projecting therefrom, each of said ribs having a rounded outer portion and the sides of each of said ribs being convergent as they approach the central portion of said bar.

3. A bar of metal having a central portion and radially disposed ribs projecting therefrom, each of said ribs having a rounded outer portion, the sides of each of said ribs being convergent as they approach said central portion, and each of said ribs and central portions having a substantially eqaul mass of metal.

4. A bar of metal especially adapted for the formation of weldless chain and comprising a central portion and four radially and eqnally spaced ribs projecting therefrom, each of said ribs and said central portion having a snbstantially equal mass of metal.

'5. A bar of metal especially adapted for the formation of weldless chain and comprising a central portion and four radially and equally spaced ribs projecting therefrom, the outer portion of each of said ribs having a' greater diameterthan the inner portion connecting said rib to the central portion of the bar.

In testimony Whereof, I hereuntoax my signature.

VVILLIM BARNUM COWIJES. 

